3 Answers
3

Apparently this error occurs when GRUB can't find a usable grub.cfg. Since the boot configuration isn't there, GRUB drops you to the grub-rescue prompt. Following these instructions you should be able to boot Ubuntu.

Its sounds like you have made a partition for the install files that is small enough that is is getting the messages Ubuntu added to make users aware of running out of space. It shouldn't hurt anything unless the OS grows beyond the amount of extra you have. The simple solution is to install GParted found in the Ubuntu Software-Center. You can simply drag the portion used as the swap space to make it a little bigger and stop the warnings. It's best to do it soon since there's always a small possibility of data loss when changing partition sizes.